MathDB
Problems
Contests
National and Regional Contests
India Contests
India IMO Training Camp
2024 India IMOTC
3
3
Part of
2024 India IMOTC
Problems
(1)
Impossible Infinite Sequence
Source: India IMOTC 2024 Day 1 Problem 3
5/31/2024
Let
P
(
x
)
∈
Q
[
x
]
P(x) \in \mathbb{Q}[x]
P
(
x
)
∈
Q
[
x
]
be a polynomial with rational coefficients and degree
d
≥
2
d\ge 2
d
≥
2
. Prove there is no infinite sequence
a
0
,
a
1
,
…
a_0, a_1, \ldots
a
0
,
a
1
,
…
of rational numbers such that
P
(
a
i
)
=
a
i
−
1
+
i
P(a_i)=a_{i-1}+i
P
(
a
i
)
=
a
i
−
1
+
i
for all
i
≥
1
i\ge 1
i
≥
1
.Proposed by Pranjal Srivastava and Rohan Goyal
number theory